Hydraulically controlled transmission



Aug. 1, 1950 c. L. FENG 2,517,188

HYDRAULICALLY CONTROLLED TRANSMISSION Filed March 51, 1947 3Sheets-Sheet l Inventor Chung Liao Feng mm m Sv Aug. 1, 1950 c. 1 FENGHYDRAULICALLY CONTROLLED TRANSMISSION Filed March 3l, 1947 3Sheets-Sheet 2 uq (o Q0 ro a '2- *E 0 Q Si E S- J," g g um: om lo lu wwwIZ un i s', Q v E i )U I l 0 0J S', lI a f g X f l o C0 I N Ng O o e 2l) Lf o i 0 1** :o N d' N Q W I N, w Il l. O um n Hi N m u fl gdr N E II a l: Y0 jj Inventar Chung Liao Feng ma. By M d/wey 19. Mey;

Aug. l, 1950 c. L. FENG HYDRAULICALLY coNTRoLLED TRANSMISSION 3shams-sheetv 3 Filed Mar'ch 3l, 1947 .w .El

Ifzvenitor Chung Liao Feng Wawy U;

l 2,517,188 HYDBAULICALLY CONTROLLED TRANSMISSION Chung Liao Feng,Philadelphia, Pa.

Application March 31, 1947, Serial No. 738.451

8 Claims. (Cl. i4-687) This invention relates generally to powertransmissions, and more particularly to a hydraulically controlledtransmission for connection with a drive shaft and a driven shaft, andcomprising a sun gear secured to the drive shaft with a plurality oiplanetary gears rotatably mounted on said driven shaft and a ring gearengaged with the planetary gears, the ring gear being operativelyconnected with a hydraulic system including a pair of hydraulic pumps,variable speed and reversal of direction of the driven shaft beingaccomplished by varying the capacity of one of the pumps.

A primary object of this invention is to provide means whereby aninfinite number of rotational speed ratios may be obtained, the driveshaft and the driven shaft being maintained in constant mechanicalconnection. Another object of this invention is to provide means wherebya reversal of the driven shaft may be obtained without reversal of thedrive shaft.

rStill another object Vof this invention is to provide means whereby apair of hydraulic pumps, one of which is of variable capacity, may beoperatively connected with a power transmission, to vary the speed of aring gear, in order to provide for the above described variation inrotational speed ratios.

Still another object of this invention is to provide means whereby thedierential in pressure between the two sides of one of these pumpsfunctions to automatically change said speed ratios.

Another object of this invention la` to combine with the pressurecontrol system described in the immediately preceding object with anauxiliary system embodying ratio control dependent upon the rotationalspeed of the drive shaft, this last feature of the invention being ofparamount importance when the device is applied "to a relatively smallpowered prime mover anda varying load.

Another object of this invention is to provide a transmission meanswhich is ideally suitable for use with automotive vehicles, and isfurther An last object to be speciilcally mentioned is to provide a device of this character which is relatively inexpensive and practicableto manufacture, extremely simple to install, adjust and use, and whichwill give generally e'lcient and durable service.

With these objects definitely in view, this invention resides in certainnovel features of construction, combination and arrangement of parts andportions as will be described hereinafter in detail and particularlypointed out in. the claims hereunto appended, and illustrated in theaccompanying drawings which form a material part of this application,and in which- Figure l is a diagrammatic view of the elements of thisinvention;

Figure 2 is a very similar view, the main ele-I ments of the inventionbeing illustrated in elevation, rather than in section, as in Figure l,go the figure including a diagrammatic sketch of a adapted for such usewith auxiliary means adapt-v possible electrical control system;

Figure 3 is a vertical transverse sectional view, taken on the line 3--3in Figure 2 Figure 4 is a vertical transverse sectional view, taken onthe line 4 4 in Figure 1 Figure 5 is a similar View, taken on the line5--5 in Figure 1, and it should be noted that Figures 4 and 5 areadapted to illustrate how the pump of variable capacity may beconstructed; and

Figure 6 isa vertical sectional view of a portion of the speed ratiocontrol system, particularly the portion embodying control according tothe speed of the drive shaft, the view being taken on the line 6 6 inFigure 2.

Similar characters of reference designate similar or identical parts andportions throughout the specication and throughout the several views ofthe drawings.

Referring now to these drawings in detail, it will be apparent that thedevice is adapted for use with a drive shaftI I0 and a driven shaft I2,the bearings for which are deleted from these drawings as not beingmaterial to this invention.

The driven shaft I2 is provided with a frame member I4 rigidly securedon the end thereof and this frame is provided with stub shafts IS, uponwhich are freely rotatably mounted a similar number of planetary gearsI8. The bearings of these planetary gears may be of any suitablecharacter, the essential feature thereof -being the proper retention ofthe planetary gears I8 on the outer ends of the stub shafts I6. A ringgear 22 is interiorly geared to engage the planetary gears I8 and isfreely rotatably mounted,

3 coaxially with the drive shaft i0. and preferably on a suitablebearing 24 provided adjacent the end of the said drive shaft. A sun gear20 is rigidly secured to the extremeend of the drive 4 Y tubes 02 andI4. respectively, the action of the surge chambers being to absorb andlessen the eect of sudden changes in the load on the driven shaft I2,the torque on the drive shaft I0. or, more directly. in the rate of flowof the hydraulic fluid through the several tubes, each surge chambercomprising a casing rigidly secured to the ends of the extendingportions 12 84. and means for automatically controlling the capacity ofthe variable capacity Lpump 00, which will be hereinafter described.With the pump 30 at full capacity, the ring gear 22 is rotated atsufficient speed to cause reversal of the driven shaft i2.

The hydraulic pump 28. which actually functions as a hydraulic motorrather than as a pump. is controlled by the rate of flow of hydraulicfluid from thc tube 02, and the impeller of this pump or motor 28 isconnected tothe gear wheel 38 by a short shaft 38, suitable bearingsbeing provided, of course, to maintain this gear 38 in engagement withthe ring gear 22. The rate of flow of the hydraulic fluid will.therefore, be seen to be the factor controlling or determining whetherthe ring gear 22 will be accelerated or alternatively braked orretarded. The variable capacity pump `3|) is also connected to the tubes32 and 34` and may be of the character illustrated in the drawingscomprising an impeller 40, a similar impeller 42, and an idler 44,mounted in a suitable casing 4B. The impeller 40 is driven by a shortshaft 48 connected to the pinion 50 which is, in turn, driven by thegear 52 rigidly secured on the drive shaft |0. Guide members 54 and 56of disc form are provided on the outer ends of the impeller 42 and theidler 44, and all these last-mentioned parts are secured to the controlshaft 08. The idler 4'4 will preferably be formed with an arcuate upperface 60 having only a small clearance from the teeth or blades of theimpeller 40, This idler must be retained from rotation and the casing 48will, to that end, be provided with flat, longitudinally disposed ribportions 82 against which the fiat side faces 64 of the upper portionofthe idler 44 abut and slide. The capacity of the pump 30 may, by aconstruction analogous to that described immediately above, be varied bylongitudinal movement of the assembly including the impeller 42 and theidler 44, and the control rf the capacity of this pump is delegated tothe shaft 50, this shaft being moved longitudinally either manually orautomatically,as will be hereinafter described. In this connection, itshould be carefully noted that the tube I2 is connected to the variablecapacity pump 00 on the side thereof illustrated as to the front inFigure l, and the tube 34 is connected to this pump as to the rear inFigure l. this arrangement being more clearly illustrated in Figures 4and 5. Furthermore, it should be noted that the inlet and outlet of thispump must be arranged to remain operative for all positions of theimpeller 42,

as indicated by the elongated inlet 04', shown in dotted outline 80.

A pair of surge chambers 80 and 10 are connected to extending portions12 and 14 of the and 14 of the tubes, a piston member 1l and a springcompressed between the end of the casing and the piston member. asindicated at 14.

Referring now to the means for automatically controlling the rate offlow of hydraulic fluid through the tubes and the pump or motor 24, thedrive shaft |0 has rigidly secured thereto a gear 00 which isoperatively engaged with a gear l2 mounted for free rotation upon acasing I4. This casing la provided with a cylinder 00 and a piston 0Iterminally connected on the end of the piston rod 00, the cylinder 40communicating with the tube l2 and the piston 00 being urged,

.as to the left in Figure 1, by the pressure of the fluid in the tube32. A very similar cylinder l2 is connected to the tube I4 and a piston04 is reciprocatively mounted within this cylinder and connected to apiston rod 94. The adjacent ends of the piston rods 90 and 0I are ioinedtogether by a cross member 00 and a fluted shaft |00 slidably mounted inone end of the casing 44. It willbe evident that increase of pressure inthe tube I2 will be accompanied by decrease of pressure in the tube 24,and vice versa, and that the pistons and 94 will be acted uponsimultaneously and that the fluted shaft |00 will be moved as tothe leftwhen pressure is increased in the tube 02, that is, when the capacity ofthe pump 30 is increased. When the fluted shaft` |00 is moved to theleft, the collar |02 is maintained out of engagement with the slidingsleeve |04 which is interiorly fluted to move freely longitudinally onthe fluted shaft |00 and to turn therewith, a right angular flangeportion |08 of this sliding sleeve being provided to act as an actuatingmember for the electric control sys'- tem of the device.

A third cylinder |00, similar to the cylinders described above andcommunicating with the brake system, when this device is used on anautomotive vehicle, is provided with a piston ||0 and a piston rod l|2which is secured to the cross member 00. Application of the brakes tosuch an automotive vehicle will be made to increase the pressure of thehydraulic fluid contained behind the piston ||0 in the cylinder |00 andthe fluted shaft |00 will be moved, as to the right in Figure l,.so thatthe collar |02 will contact the slidlng sleeve |04 and force the same tothe right. to give the same electric signal, as hereinafter described.as is given when the pressure of the hydraulic fluid in the tube 34 isconsiderably in excess of the pressure in the tube $2. It will be seenthat increase of load on the driven shaft |2 `or application of brakesto an automotive vehicle in which this device is installed will,therefore, tend to move the control elements in the same direction,while increase of rotational speed of the drive shaft l0 will increasethe rotational speed of the gear l2. A pair of attachment flanges ||2are rigidly secured to this gear 42 and a pair of bell cranks |I4 arepivotaliy secured to the other ends of these flanges H2. A helicalspring ||4 is tensioned between the corresponding arms of the bellcranks ||4 and the other pair of corresponding arms ||0 of the bellcranks are made to engage a groove in one end of the sliding sleeve l.|4. Increase of rotational speed of the-shaft I0 will, therefore, tendto cause the outer ends of 4,the bell cranks ||4 to diverge after themanner oi' lily weights in a governor and the sleeve |04 will be movedas to the left in Figure 1.

TheLspeed ratios can be manually controlled by longitudinal movement ofthe control shaft 58, but it is preferred that a hydraulic, mechanicalor electrical means be incorporated with this device in order to providefor automatic control of the said speed ratios to correspond with thevarying load on the shaft I2 and the.speed of the drive shaft I 0.Accordingly, a bifurcated member I| is suitably mounted forreciprocative movement in contact with a pair of sliding contact strips|22 and |24. It will be noted that the actual contact member of themember |20 is insulated froml thebiturcated portion which is in contactwith the metallic flange member |06. A

source of direct current is connected to the contact plate |22 and bothcontact strips |22 and |24 are, of course, insulated, the latter beingdiivided by an insulating dead spot |20. The end |20 of the contactstrip |24 is connected through a master switch and a control switch |32,through an accelerator switch |34; opened when lthe' accelerator leveris retracted to oil or neutral position, and thence directly to oneterminal vof a reversible motor |36. The other end of the contact strip|24 is connected directly to the con- -tact strip |38 which coacts witha similar contact strip divided into two portions |40 and |42, a brushv|44 being provided to connect these contact strips' and operated by amember |46 associated with the control shaft 50, it being understoodthat the elements herein illustrated in the drawings and described arenot presented as properly detailed mechanical units and that thedrawings are diagrammatic in character. One end of each of the contactstrip portions |40, |42 is connected .to a terminal of the reversiblemotor |36 and to :the previously mentioned terminal of the motor,respectively, the' end |44 being connectabie through the acceleratorswitch |34 tothe end |22 of the contact strip |24 when the manualcontrol switch |22 is moved into "reverse position.

It isthought that the manual operation of this invention will be clearlyunderstood from the foregoing description and the electrical orautomatic operation is, in many respects, very similar to the manualcontrol. For example, when the various elements are in the positionsrepresented in Figure 2, the rotational speed of the drive shaft it maybe gradually increasing and while the pressure of the hydraulic fluid isgreater in the tube 22 than in the tube 34 and thus still forcing thepump or motor '28 to brake the ring g'ear 22, the gradual increase ofthe speed in the drive shaft ill will also gradually force the guidingsleeve |14 as to the left, moving the switch brush |22 to the left. Whenthe Vswitch brush |22 reaches the dead spot |26, the current will be cutod from the motor |26, the operation of this motor, up until this pointis reached, being such as to force the control shaft 58 as to the right,that is, io close or render the variable capacity pump 30 ineffective.It will be noted that ,the brush wiper arm |44 will remain on contact|40 for all forward movement and on contact |42 for all reversemovement. When the flow of hydraulic fluid through the tubes is reducedto a minimum or completely inhibited, the transmission will befunctioning in substantially l-l ratio, corresponding to high gear in anordinary automotive vehicle. When the load is increased on the drivenshaft |'2, a reverse action of the various elements is initiated by themovement of the ily weight bell cranks ||4 under the influence of thespring IIB, as a result, of course, of the reduction in the rotationalspeed of the drive shaft I0.

A very similar action occurs when the device is switched to the reverseposition by means of the manual control switch |32. With the drive shaftI0 still rotating in the same direction and at a relatively high speed,the switchbrush member |20 will connect the source of electrical powerto the portion |28 and the other terminal of the electric motor |36 willbe directly connected. When the engine is speeded up, the acceleratorswitch |34 will be closed and the y weigh-t bellcranks will operate toi'orce the brush member |20 onto the portion |28. Furthermore, the motor|36 will be energized and the pump 30 will be adjusted for full capacityoperation. As ex vplained above, at full capacity operation of pump 30,the ring gear 22 and sun gear 26 will be rotated suiliciently fast toresult in a reverse drive of the shaft |2. As will be evident from thedrawings, the electrical connections are easily made so that thereversible motor |35 acts in unison and as an auxiliary to the manualcontrol. Finally,

it should be noted that braking action with the l 'resultant increase ofpressure in the tube 34 and the mechanical forcing of the slide |04 asto the right in Figure 2 is prevented from changing the ratio past thezero or neutral position, since movement of the sliding brush member |20onto the right-hand end of the'contact strip |24 will immediately arrestthis action as the elements will then be in a position as indicated inFigure 2. It will thus be seen that reversal of the transmission willnot result from an application of the brakes.

Obviously no attempt has been made in this application to describe thevarious modifications of structure whereby this invention may beimplemented and reduced to practice, and though there has been shown aparticular embodiment of this invention, this application is not limitedto this particular embodiment, but it is desired to include in the scopeof this invention the construction, combination `and arrangement ofparts and portions substantially as set forth in the appended claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A hydraulically controlled transmission for connection with a driveshaft and a driven shaft, comprising a. sun gear secured to said driveshaft, a frame rigidly secured to said driven shaft, planetary gearsrotatably mounted on said frame, a ring gear engaged with said planetarygears and mounted for free rotation coaxially with said.

sun gear, a hydraulic system including a pair of hydraulicallyinterconnected hydraulic pumps operatively connected to said ring gearand said drive shaft respectively, and governor means operated by saiddrive shaft to vary the capacity of one of said pumps.

2. A hydraulically controlled transmission for connection with a driveshaft and a driven shaft, comprising a sun gear secured to said driveshaft, a frame rigidly secured to said driven shaft, planetary gearsrotatably mounted on said frame, a ring gear engaged with said planetarygears and mounted for free rotation coaxially with said sun gear, ahydraulic system including a pair of hydraulically interconnectedhydraulic pumps operatively connected to said ring gear and said driveshaft respectively, and governor means operated by said drive shaft tovary the capacity of one of Said pumps in accordance with the speed ofrotation of the drive shaft.

3. A hydraulically controlled transmission for connection with a driveshaft and a driven shaft, comprising a sun gear secured to said driveshaft, a frame rigidly secured to said driven shaft, planetary gearsrotatably mounted on said frame, a ring gear engaged with said planetarygears and mounted for free rotation coaxially with said sun gear, ahydraulic system including a pair of hydraulically interconnectedhydraulic pumps operatively connected to said ring gear and said driveshaft respectively, and means to vary the capacity of one of said pumpsin accordance with the speed of rotation of the drive shaft and the loadon the driven shaft comprising a governor having a shaft driven by saiddrive shaft, a sliding sleeve on said shaft of the governor and turnedthereby, rotational speed responsive means to bias said sleeve intoshifting on its shaft according to the speed of said drive shaft, saidvariable capacity pump having fluid impelling gears, a control shaftadapted for shifting one of said gears relative to the other of saidgears, and means for operatively connecting said sleeve with saidcontrol shaft.

4. A hydraulically controlled transmission for connection with a driveshaft and a driven shaft, comprising a sun gear secured to said driveshaft, a frame rigidly secured to said driven shaft, planetary gearsrotatably mounted on said frame, a ring gear engaged with said planetarygears and mounted for free rotation coaxially with said sun gear, ahydraulic system including a pair of hydraulically interconnectedhydraulic pumps operatively connected to said ring gear and said driveshaft respectively, and means to vary the capacity of one of said pumpsin accordance with the speed of rotation of the drive shaft and the loadon the driven shaft, said load being gauged according to varyingdifferential in pressures on the two sides of one of said pumps by apiston acted upon by said pressures simultaneously, and means forvarying the capacity of said one pump in sympathy with the shifting ofsaid piston.

5. A hydraulically controlled transmission for connection with a driveshaft and a driven shaft, comprising a sun gear secured to said driveshaft, a frame rigidly secured to said driven shaft, planetary gearsrotatably mounted on said frame, a ring gear engaged with said planetarygears and mounted for free rotation coaxially with said sun gear, ahydraulic system including a pair of hydraulically interconnectedhydraulic pumps operatively connected to said ring gear and said driveshaft respectively, and means to vary the capacity of one of said pumps,said one of said pumps having a variable capacity sufficient to causesufficient variation in the rotational speed of said ring gear to effectreversal as well as variable speed of rotation of said driven shaft saidmeans comprising a governor having a shaft driven by said drive shaft, asliding sleeve on said shaft of the governor and turned thereby,rotational speed-responsive means to bias said sleeve into shifting onits shaft according to the speed of said drive shaft, said variablecapacity pump having iluid impelling gears, a control shaft adapted forshifting one of said gears relative t( the other of said gears. andmeans for operatively connecting said sleeve with said control shaft.

6. A transmission according to claim' 3, and wherein said last-mentionedmeans includes an electric motor operatively associated with saidcontrol shaft, and an electric circuit including a source of energy andsaid motor. and switch means operated by said sleeve and controllingsaid circuit.

7. A hydraulically controlled transmission for connection with a driveshaft and a driven shaft, comprising a sun gear secured to said driveshaft, a frame rigidly secured to said driven shaft, planetary gearsrotatably mounted on said frame, a ring gear engaged with said planetarygears and mounted for free rotation coaxlally with said sun gear, ahydraulic system including a pair of hydraulically interconnectedhydraulic pumps operatively connected to said ring gear and said driveshaft respectively, and means to vary the capacity of one of said pumpsin accordance with the speed of rotation of the drive shaft and the loadon the driven shaft, comprising a piston acted upon by pressures on thetwo sides of one of said pumps simultaneously, and means for varying thecapacity of said one pump in sympathy with the shifting of said piston,said lastmentioned means also including an electrical circuit which maybe made inoperative to allow manual control of said control shaft, saidpiston being also connected for being biased in one di- ;ection by aforce applied from outside the sys- 8. A transmission according to claiml, and including a surge chamber on each side of the pump havingvariable capacity.

CHUNG LIAO FENG.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS ANumber Name Date 1,077,454 Cooke Nov. 4, 19131,197,789 Bluemel Sept. l2, 1916 1,981,805 Kacer et al Nov. 20, 19342,173,855 Orshansky Sept. 26, 1939 2,212,046 Ross Aug. 20, 19402,373,138 Morith Apr. 10, 1945 FOREIGN PATENTS Number Country Date556,470 France Apr. 14, 1923

